A local tissue oxygen saturation detection system for postoperative free flaps

Abstract

The application discloses a kind of local tissue oxygen saturation detection systems for postoperative free flap, including front-end flexible detection module and rear-end signal processing module;Front-end flexible detection module includes the flexible packaging layer of flexible material and the interface layer of being arranged on packaging layer, the material of interface layer is hydrogel mixture, and the detection circuit for being encapsulated in packaging layer is used to detect the blood oxygen saturation of human tissue;Rear-end signal processing module is connected with the front-end flexible detection module, and the rear-end signal processing module processes the signal detected by the front-end flexible detection module, and the local tissue oxygen saturation information is obtained by calculating detection signal.This application is all designed with flexibility, avoids the mechanical damage of detection part to measurement site, so that the sensing part can better adhere to the surface of human skin, improve the accuracy of measurement and the comfort of patient.

Description

Technical Field

[0001] This invention specifically relates to a local tissue oxygen saturation detection system for postoperative free flaps. Background Technology

[0002] The development of modern science and technology has provided the medical field with more sophisticated instruments and equipment. Supported by technologies such as big data, medical equipment is gradually evolving towards intelligence, digitalization, and computerization. In the field of electronic information technology, emerging electronics such as flexible electronics are developing rapidly. Flexible electronics, due to its unique extensibility, good wearability, and advantages such as large-scale manufacturing and low cost, and because it differs from traditional rigid circuits, can achieve bending, stretching, and extension functions, and is widely used in medical, energy, military, and education fields. With the continuous integration of flexible electronics technology and modern medical technology, the flexibility of medical devices has become possible. Flexible medical devices can better conform to the human body, providing patients with greater comfort while ensuring measurement accuracy.

[0003] Traditional methods for detecting local tissue oxygenation primarily utilize near-infrared spectroscopy (NIRS). Based on the generalized Lambert-Beer law, near-infrared light allows for non-invasive measurement of blood oxygen concentration in tissues such as the human body, brain, and skeletal muscle, providing a comprehensive understanding of tissue oxygen consumption and blood supply under different environments. Therefore, by using near-infrared light with wavelengths between 700 and 1000 nm, the different absorption rates of near-infrared light by oxyhemoglobin and deoxyhemoglobin in tissues allow for precise calculation of tissue oxygen saturation. This enables non-invasive, real-time, and accurate monitoring of local tissue blood oxygenation.

[0004] Currently, most commercially available localized tissue oxygen monitoring instruments use rigid circuit boards for their probes, which cannot adhere closely to the skin. Furthermore, since the monitoring sites are often damaged areas of the skin, the rigid circuit boards can easily cause mechanical damage. Additionally, research shows that localized tissue oxygen monitoring often requires continuous monitoring for 24 or 48 hours, and existing probes experience decreased viscosity and bacterial contamination during prolonged continuous monitoring. Therefore, designing flexible probes is crucial for reducing skin damage and improving measurement accuracy. Moreover, commercially available localized tissue oxygen monitoring instruments are relatively large and mostly wired, making them inconvenient to use and move. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a local tissue oxygen saturation detection system for postoperative free flaps, which addresses the above-mentioned defects in the existing technology. The system adopts a flexible design throughout, avoiding mechanical damage to the measurement site by the detection part, and allowing the sensing part to better fit the human skin surface, thereby improving the accuracy of measurement and the patient's comfort.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] A local tissue oxygen saturation detection system for postoperative free flaps includes a front-end flexible detection module and a back-end signal processing module;

[0008] The front-end flexible detection module includes a flexible encapsulation layer made of flexible material and an interface layer disposed on the encapsulation layer. The interface layer is made of a hydrogel mixture and is directly adhered to human skin. The detection circuit encapsulated in the encapsulation layer is used to perform non-invasive detection of blood oxygen saturation in human tissue and obtain a signal of local tissue oxygen saturation.

[0009] The back-end signal processing module is connected to the front-end flexible detection module. The back-end signal processing module processes the signals detected by the front-end flexible detection module and calculates the local tissue oxygen saturation information from the detection signals. The calculated local tissue oxygen value is then sent to the mobile device or display.

[0010] According to the above technical solution, the front-end flexible detection module also includes a flexible substrate layer, a conductive layer, and a chip layer. The flexible substrate layer and the flexible encapsulation layer are used to cooperate in constructing the flexible frame body of the front-end flexible detection module. The conductive layer and the chip layer are both located within the flexible frame body. The conductive layer and the chip layer constitute the detection circuit. The chip layer is used to emit and detect near-infrared light, thereby performing non-invasive detection of blood oxygen saturation in human tissue. The conductive layer is used to conduct electrical signals from the chip layer.

[0011] According to the above technical solution, the detection circuit in the chip layer includes a light emitter and a light sensor; the conductive layer is a conductive silver paste with stretchable properties after curing, which serves as a wire; and the material of the flexible encapsulation layer is polydimethylsiloxane (PDMS).

[0012] According to the above technical solution, the hydrogel mixture used as the interface layer material is composed of acrylic monomer, methacryloyloxyethyltrimethylammonium chloride cationic monomer, α-ketoglutarate, N,N'-methylenebisacrylamide, ε-polylysine and ε-polylysine-dopamine isothiocyanate functional component monomer, and polylysine.

[0013] According to the above technical solution, the back-end signal processing output module includes a core processor module, a program reset module, a USB to serial port module, a communication port, and a driver module; the core processor module is connected to the signal input terminal of the program reset module; the core processor module is connected to the USB to serial port module to realize serial communication and program download; the core processor module is connected to the signal input terminal of the communication port; the communication port is connected to the front-end flexible detection module; and the core processor module is connected to the signal input terminal of the transmitting module.

[0014] According to the above technical solution, the back-end signal processing output module also includes a power supply module, which includes a battery power supply module and a power conversion module. The input terminal of the power conversion module is connected to the output terminals of the battery power supply module and the USB power supply module. The battery power supply module is used to provide voltage, and the power conversion module is used to increase the fixed voltage provided by the battery power supply module. At the same time, when using USB power supply, it can be used to reduce the voltage provided by USB to the corresponding value.

[0015] According to the above technical solution, the back-end signal processing output module also includes a driver module and an FPC connection port. The core processing module is connected to the driver module and the FPC connection port respectively, and the driver module and the FPC connection port are connected to the front-end flexible detection module respectively.

[0016] According to the above technical solution, the preparation method of the front-end flexible detection module includes the following steps: First, polydimethylsiloxane (PDMS) is spin-coated and cured on a rigid substrate to obtain a flexible material substrate layer composed of PDMS; then, conductive silver paste that meets the pre-designed circuit pattern is prepared on the flexible substrate layer by a scraping method to form a conductive layer; then, multiple chips are connected at the pre-set target positions of the conductive silver paste layer to obtain a chip layer, which is then cured. After curing, the conductive silver paste layer forms a conductive layer. The pins of each chip are bonded to the conductive silver paste layer by applying conductive silver paste and then lightly pressing it; next, PDMS is poured onto the chip layer as a flexible encapsulation layer. After curing in an oven, the chips are fixed and protected; then, the encapsulation layer (PDMS) is treated with benzophenone solution, and a pre-crosslinked hydrogel solution is injected into a mold on the encapsulation layer, covered with a quartz glass plate, and irradiated with ultraviolet light to obtain a fully crosslinked self-adhesive antibacterial and anti-swelling hydrogel interface layer, finally obtaining the front-end flexible blood oxygen detection module.

[0017] According to the above technical solution, the preparation method of the hydrogel solution includes the following steps: First, 10-20 wt% acrylic acid monomer and 10-15 wt% methacryloyloxyethyltrimethylammonium chloride cationic monomer are dissolved in 10 ml of deionized water. After thorough stirring, 0.1 wt% α-ketoglutarate and 0.02 wt% N,N'-methylenebisacrylamide (MBAA) are added sequentially. After stirring, 5%-10 wt% ε-polylysine-dopamine isothiocyanate functional component (EPL-DA-ITC) monomer and 2-5 wt% ε-polylysine (EPL) are added to the above solution. After ultrasonic vibration, the solution is degassed to obtain a pre-crosslinked hydrogel solution.

[0018] According to the above technical solution, the front-end flexible detection module is connected to the back-end signal processing module through an FPC flexible flat cable. One end of the six connection ports of the FPC flexible flat cable is bonded to the conductive layer of the front-end flexible blood oxygen detection circuit through conductive silver paste, thereby realizing the connection between the FPC cable and the front-end flexible port. The other end is connected to the back-end signal processing output module through a PFC connector. Finally, the back-end signal processing output module is connected to the front-end flexible blood oxygen detection circuit via the FPC connection flexible flat cable, thus obtaining a local tissue oxygen saturation detection system.

[0019] The present invention has the following beneficial effects:

[0020] 1. By designing the front-end detection module with flexibility, the front-end detection module can better conform to human skin, reducing damage to human tissues; the front-end flexible detection module adopts a flexible design throughout, avoiding mechanical damage to the measurement site by the detection part, allowing the sensing part to better fit the surface of human skin, improving the accuracy of measurement and patient comfort.

[0021] 2. The interface layer of the aforementioned flexible front-end detection module possesses self-adhesive, antibacterial, and anti-swelling properties, ensuring accurate measurements over extended periods while minimizing damage to the patient's skin. Simultaneously, hydrogel is used as the interface material, and functional materials are introduced to imbue it with self-adhesive and antibacterial properties. Furthermore, due to the exudation of sweat and tissue fluid from the skin at the measurement site, absorption by the hydrogel interface can impair the mechanical properties of the entire interface layer; therefore, anti-swelling materials are added to the interface layer to reduce the swelling ratio. The entire system is compact, lightweight, stable, and highly accurate. The fabrication process of the aforementioned flexible front-end detection module is simple, allowing for the creation of front-end sensing modules of different sizes to meet varying detection depth requirements, facilitating manufacturing and widespread application. Attached Figure Description

[0022] Figure 1 This is a process diagram of the fabrication method of the front-end flexible detection module in this embodiment of the invention;

[0023] Figure 2 This is a schematic diagram of the composition of the hydrogel in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the front-end flexible detection module in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the circuit principle of the back-end signal processing module in an embodiment of the present invention;

[0026] In the diagram, 1-flexible substrate layer, 2-common rigid substrate layer (such as glass slide, silicon wafer, acrylic, etc.), 3-polyester stencil, 4-scraper, 5-conductive silver paste layer, 6-chip layer, 6-1-SMT 735 / 850nm dual-wavelength LED, 6-2-OPT3002 light intensity sensor, 7-liquid flexible material, 8-acrylic mold, 9-flexible encapsulation layer, 10-benzophenone solution, 11-prepolymerized hydrogel solution, 11-1-acrylic monomer, 11-2-methacryloyloxyethyltrimethylammonium chloride cationic monomethyl methacrylate, 11-3-α-ketoglutaric acid, 11-4-N ,N'-Methylenebisacrylamide, 11-5-ε-polylysine, 11-6-ε-polylysine-dopamine isothiocyanate functional component monomers, 12-quartz glass plate, 13-75W, 365nm UV lamp, 14-fully polymerized hydrogel interface layer, 15-ESP32 core processing module, 16-Bluetooth antenna transmitting module, 17-Power conversion module, 18-I2C communication port, 19-USB to serial port module, 20-Button battery powered module, 21-Program reset module, 22-LED driver module, 23-FPC flexible cable, 24-Front-end flexible detection module, 25-Tissue oxygen APP terminal. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] Reference Figures 1-4 As shown, the local tissue oxygen saturation detection system for postoperative free flaps provided in Embodiment 1 of the present invention includes a front-end flexible detection module and a back-end signal processing module.

[0029] The front-end flexible detection module includes a flexible encapsulation layer made of flexible material and an interface layer disposed on the encapsulation layer. The interface layer is made of a hydrogel mixture and is directly adhered to human skin, so that the flexible front-end detection module can adhere to the user's skin epidermis. The detection circuit encapsulated in the encapsulation layer is used to perform non-invasive detection of blood oxygen saturation of human tissue using near-infrared spectroscopy technology to obtain a signal of local tissue oxygen saturation.

[0030] The back-end signal processing module is connected to the front-end flexible detection module. The back-end signal processing module processes the signal detected by the front-end flexible detection module and calculates the local tissue oxygen saturation information based on steady-state spectral spatial resolution technology. Finally, the calculated local tissue oxygen value is sent to the mobile terminal through the Bluetooth antenna transmission module.

[0031] Furthermore, the front-end flexible detection module also includes a flexible substrate layer, a conductive layer, and a chip layer. The flexible substrate layer is disposed on the flexible encapsulation layer. The flexible substrate layer and the flexible encapsulation layer are used to cooperate in constructing the flexible frame body of the front-end flexible detection module. The conductive layer and the chip layer are both located within the flexible frame body. The conductive layer and the chip layer constitute the detection circuit. The chip layer is used to emit and detect near-infrared light, thereby performing non-invasive detection of blood oxygen saturation in human tissue. The conductive layer is used to conduct electrical signals from the chip layer.

[0032] Furthermore, the detection circuit within the chip layer includes an LED emitter of model SMT735 / 850 and a photosensitive sensor of model OPT3002; the conductive layer is made of conductive silver paste with stretchable properties after curing as a conductor; and the flexible encapsulation layer is made of polydimethylsiloxane (PDMS).

[0033] Furthermore, the front-end flexible detection module specifically utilizes SMT735 / 850 LEDs to generate light at wavelengths of 735nm and 850nm, and uses an OPT3002 to detect the intensity of light reflected back from the human body. Within this front-end flexible detection module, a conductive silver paste with stretchable properties after curing is used as a conductor to conduct electrical signals. The conductive silver paste is prepared by mixing silver powder and polydimethylsiloxane at a mass ratio of 3:1. The flexible encapsulation material is polydimethylsiloxane (PDMS), and the interface layer material is a hydrogel mixture.

[0034] Furthermore, the hydrogel mixture serving as the interface layer material is composed of acrylic acid monomer, methacryloyloxyethyltrimethylammonium chloride cationic monomer, α-ketoglutarate, N,N'-methylenebisacrylamide, ε-polylysine and ε-polylysine-dopamine isothiocyanate functional component monomer, and polylysine.

[0035] Furthermore, the back-end signal processing output module includes an ESP32 core processor module, a program reset module, a USB-to-serial module, an I2C communication port, and an LED driver module. The ESP32 core processor module mainly includes U0TXD, U0RXD, GPIO0, EN, SCL, SDA, IO19, IO21, and a LAN_IN port. The EN port of the ESP32 core processor module is connected to the signal input of the program reset module. The U0TXD, U0RXD, GPIO0, and EN ports of the ESP32 core processor module are connected to the USB-to-serial module to enable serial communication and program download. The SCL and SDA ports of the ESP32 core processor module are connected to the signal input of the I2C communication port. The IO19 and IO21 ports of the ESP32 core processor module are connected to the LED driver module, and the LED driver module and the I2C communication port are connected to the front-end flexible detection module. The LAN_IN port of the ESP32 core processor module is connected to the signal input of the Bluetooth antenna transmitter module.

[0036] Furthermore, the back-end signal processing output module also includes a power supply module, which comprises a button battery power supply module and a power conversion module. The input terminal of the power conversion module is connected to the button battery power supply module and the USB power supply output terminal. The button battery power supply module provides a 3V voltage, and the power conversion module boosts the fixed voltage provided by the button battery power supply module to 3.3V. Simultaneously, when using USB power, it can be used to reduce the 5V voltage provided by USB to the corresponding 3.3V. The battery conversion module is a TPS63802DLAR module, and the input terminal of the TPS63802DLAR module is connected to the button battery power supply module and the USB power supply output terminal.

[0037] Furthermore, the back-end signal processing output module also includes an LED driver module and an FPC connector. The ESP32 core processing module is connected to both the LED driver module and the FPC connector, which in turn are connected to the front-end flexible detection module. The LED driver module is a TMUX6123DGSR, which enables the ESP32 core processor module to control the SMT735 / 850 LED emitter of the front-end flexible detection module. The front-end flexible detection module uses the FPC connector to perform I2C communication to obtain the light intensity signal of the OPT3002 in the front-end flexible module, and transmits the control signal of the LED driver module to the SMT735 / 850 LED emitter through the FPC connector, while simultaneously supplying power to the front-end flexible blood oxygen saturation detection circuit.

[0038] The FPC connector is connected to the front-end flexible detection module via an FPC flexible cable.

[0039] Furthermore, the front-end flexible detection module can be manufactured in different sizes according to the required detection depth; the back-end signal processing output module is a two-layer circuit, preferably with an area not exceeding 25mm × 30mm.

[0040] Furthermore, the fabrication method of the front-end flexible detection module includes the following steps: First, polydimethylsiloxane (PDMS) is spin-coated and cured onto a rigid substrate to obtain a flexible material substrate layer mainly composed of PDMS; then, conductive silver paste conforming to a pre-designed circuit pattern is prepared on the flexible substrate layer using a blade coating method to form a conductive layer; then, multiple chips are connected at pre-set target positions on the conductive silver paste layer to obtain a chip layer, followed by curing. After curing, the conductive silver paste layer forms a conductive layer. The pins of each chip are coated with conductive silver paste and then lightly coated with conductive silver paste. The conductive silver paste layer is adhered by touch and pressing. Next, polydimethylsiloxane is poured onto the chip layer as a flexible encapsulation layer. After curing in an oven at 40℃~80℃ for 2~4 hours, the chips can be fixed and protected. Then, the encapsulation layer (PDMS) is treated with 10wt% benzophenone solution for 10 minutes. The pre-crosslinked hydrogel solution is injected into the mold on the encapsulation layer, covered with a quartz glass plate, and irradiated with ultraviolet light for 1 hour to obtain a fully crosslinked self-adhesive antibacterial and anti-swelling hydrogel interface layer, and finally the front-end flexible blood oxygen detection module is obtained.

[0041] Further, the preparation method of the hydrogel solution includes the following steps: First, 10-20 wt% acrylic acid monomer and 10-15 wt% methacryloyloxyethyltrimethylammonium chloride cationic monomer are dissolved in 10 ml of deionized water and stirred thoroughly for 30 min. Then, 0.1 wt% α-ketoglutarate and 0.02 wt% N,N'-methylenebisacrylamide (MBAA) are added sequentially as initiators and crosslinking agents, and the mixture is magnetically stirred for 20 min. Then, 5%-10 wt% ε-polylysine-dopamine isothiocyanate functional component (EPL-DA-ITC) monomer and 2-5 wt% ε-polylysine (EPL) are added to the above solution. After ultrasonic vibration for 20 min, the mixture is degassed for 30 min to obtain a pre-crosslinked hydrogel solution.

[0042] Hydrogel is a three-dimensional cross-linked polymer material with high water content. It has good biocompatibility, excellent physical and mechanical properties and long-term implantation stability. Moreover, hydrogel does not adhere to the wound, making it extremely convenient to apply and remove.

[0043] Furthermore, the front-end flexible detection module is connected to the back-end signal processing module via an FPC flexible flat cable. One end of the six connection ports of the FPC flexible flat cable is bonded to the conductive layer of the front-end flexible blood oxygen detection circuit through conductive silver paste, thereby realizing the connection between the FPC cable and the front-end flexible port. The other end is connected to the back-end signal processing output module through a PFC connector. Finally, the back-end signal processing output module is connected to the front-end flexible blood oxygen detection circuit via the FPC flexible flat cable, thus obtaining a local tissue oxygen saturation detection system.

[0044] Working principle of this invention: This invention belongs to the field of medical and health testing devices, and discloses a local tissue oxygen saturation detection system and its preparation method for postoperative free flap detection. The system includes a front-end flexible detection module and a back-end signal processing module. The flexible front-end detection module uses a flexible material as an encapsulation layer, and an interface layer is designed on the encapsulation layer. This interface layer has advantages such as self-adhesion, antibacterial properties, and anti-swelling properties, allowing it to directly adhere to human skin for non-invasive detection of blood oxygen saturation in human tissue using near-infrared spectroscopy. The back-end signal processing module calculates the local tissue oxygen saturation from the detected signal using a steady-state spectral spatial resolution algorithm, and then transmits it to a mobile device via a Bluetooth antenna transmission module. This invention endows the front-end module with conformal and adhesive capabilities to human skin through structural design and interface material design. The interface material has antibacterial and anti-swelling properties, ensuring long-term adhesion to the human skin surface without causing damage. The circuit design enables the back-end signal processing module to receive, process, and transmit the front-end sensor data, achieving wireless real-time transmission and display of local tissue oxygen saturation information. The local tissue oxygen detection system provided by this invention adopts a modular design. The back-end data processing module has a built-in Bluetooth radio frequency circuit, which can transmit data to mobile terminals such as mobile phones via Bluetooth. The back-end processing circuit is a double-layer circuit board, and its area is preferably no more than 25mm×30mm.

[0045] like Figure 1 The diagram shows the fabrication process of a local tissue oxygen sensor used for postoperative free flap detection. The following example illustrates the system's fabrication process.

[0046] Example 2

[0047] a. An SMT735 / 850 LED + OPT3002 light intensity sensor is selected to implement the chip layer 6 of the front-end flexible detection module. The control port of the SMT735 / 850 LED is connected to the LED driver module 24 of the back-end signal processing module via an FPC flexible cable 23; the OPT3002 light intensity sensor communicates with the ESP32 core processing module 15 of the back-end signal processing module via an I2C bus.

[0048] b. An EPS32-PICO-D4 chip is selected as the ESP32 core processing module 15, and a CP2208 chip is selected as the signal conversion chip of the USB to serial port module 19 to realize serial communication and program download between the computer and the ESP32 core module 15. An AN2051-24 with an impedance of 50Ω is selected as the Bluetooth antenna transmitting module 16, a CR2032 button battery is selected as the power supply for the button power supply module 20, and a TPS63802DLAR is selected as the power conversion chip of the power conversion module 17 to realize the boost of the 3V power supply and the step-down of the 5V power supply, providing a stable 3.3V power supply for the ESP32 core processor module 15.

[0049] c. Polydimethylsiloxane (PDMS) is spin-coated and cured onto a rigid substrate 2 to obtain a flexible material substrate layer 1 mainly composed of PDMS; then, using a polyester stencil 3 as a mask, a conductive silver paste layer 5 conforming to a pre-designed circuit pattern is prepared on the flexible substrate layer 1 using a scraper 4 to form a conductive layer; next, multiple chips are connected to pre-set target positions on the conductive silver paste layer 5 to obtain a chip layer 6; the pins of each chip are adhered to the conductive silver paste layer by applying conductive silver paste and then lightly pressing; then cured, the conductive silver paste layer 5 forms a conductive layer after curing; then... Polydimethylsiloxane is then cast onto the chip layer as a flexible encapsulation layer 9. After curing in an oven at 40℃~80℃ for 2~4 hours, the chips can be fixed and protected. Then, the encapsulation layer (PDMS) is treated with a 10wt% benzophenone solution 10 for 10 minutes. The pre-crosslinked hydrogel solution is then injected into the acrylic mold 8 on the encapsulation layer, covered with a quartz glass plate 12, and irradiated under a 75W ultraviolet lamp 13 with a wavelength of 365nm for 1 hour to obtain a fully crosslinked self-adhesive antibacterial and anti-swelling hydrogel interface layer 14, and finally the front-end flexible detection module is obtained.

[0050] c. In this example, as Figure 2A schematic diagram of the hydrogel composition of a local tissue oxygen sensor used for postoperative free flap detection. The pre-crosslinked hydrogel solution 11 includes acrylic monomer 11-1, methacryloyloxyethyltrimethylammonium chloride cationic monomer 11-2, α-ketoglutaric acid 11-3, N,N'-methylenebisacrylamide 11-4, ε-polylysine 11-5, and ε-polylysine-dopamine isothiocyanate functional component monomer 11-6. The mass fractions of acrylic monomer 11-1, methacryloyloxyethyltrimethylammonium chloride cationic monomer 11-2, ε-polylysine-dopamine isothiocyanate functional component monomer 11-6, and ε-polylysine 11-5 are 10-20 wt%, 10-15 wt%, 5%-10 wt%, and 2-5 wt%, respectively. Acrylic acid monomer 11-1 and methacryloyloxyethyltrimethylammonium chloride cationic monomer 11-2 were dissolved in 10 ml of deionized water and stirred thoroughly for 30 min. Then, 0.1 wt% α-ketoglutarate 11-3 and 0.02 wt% N,N'-methylenebisacrylamide 11-4 were added sequentially as initiators and crosslinking agents, and the mixture was magnetically stirred for 20 min. ε-polylysine-dopamine isothiocyanate functional component monomer 11-6 and ε-polylysine 11-5 were added to the above solution, and the mixture was ultrasonically vibrated for 20 min and then degassed for 30 min to obtain pre-crosslinked hydrogel solution 11.

[0051] d. In this example, as Figure 3 A three-dimensional structural diagram of the flexible detection module at the front end of the local tissue oxygen sensor used for postoperative free flap detection. Light with wavelengths of 735nm and 850nm is alternately generated by an SMT735 / 850 LED 6-1 at 200ms intervals. The light intensity at the sensor location is measured using two OPT3002 light intensity sensors 6-2. The collected light intensity signals are then sent via I2C bus to the ESP32 core processing module 15 of the back-end signal processing module for data processing.

[0052] In this example, such as Figure 4 This is a schematic diagram of the circuit principle of the local tissue oxygen sensor for postoperative free flap detection provided by the present invention. The ESP32 core processor module 15 in the back-end signal processing module acquires the signal collected by the front-end flexible detection module 24 through the I2C communication port 18, and calculates the local tissue oxygen saturation based on a steady-state spectral spatial resolution algorithm. Then, the Bluetooth antenna transmitting module 16 transmits the local tissue oxygen information to the tissue oxygen APP terminal 25 on a mobile device. Users can obtain real-time information on the change of local tissue oxygen saturation over time at the measured site through the mobile APP.

[0053] The above are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent changes made in accordance with the claims of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A system for detecting local tissue oxygen saturation in postoperative free flaps, characterized in that, It includes a front-end flexible detection module and a back-end signal processing module; The front-end flexible detection module includes a flexible encapsulation layer made of flexible material and an interface layer disposed on the encapsulation layer. The interface layer is made of a hydrogel mixture and is directly adhered to human skin. The detection circuit encapsulated in the encapsulation layer is used to perform non-invasive detection of blood oxygen saturation in human tissue and obtain a signal of local tissue oxygen saturation. The back-end signal processing module is connected to the front-end flexible detection module. The back-end signal processing module processes the signals detected by the front-end flexible detection module, calculates the local tissue oxygen saturation information from the detection signals, and sends the calculated local tissue oxygen value to the mobile terminal. The front-end flexible detection module also includes a flexible substrate layer, a conductive layer, and a chip layer. The flexible substrate layer and the flexible encapsulation layer are used to cooperate in constructing the flexible frame body of the front-end flexible detection module. The conductive layer and the chip layer are both located within the flexible frame body. The conductive layer and the chip layer constitute the detection circuit. The chip layer is used to emit and detect near-infrared light, thereby performing non-invasive detection of blood oxygen saturation in human tissue. The conductive layer is used to conduct electrical signals from the chip layer. The detection circuit within the chip layer includes a light emitter and a photosensitive sensor; the conductive layer is made of conductive silver paste with stretchable properties after curing, serving as the conductor; the flexible encapsulation layer is made of polydimethylsiloxane (PDMS). The hydrogel mixture used as the interface layer material is composed of acrylic monomer, methacryloyloxyethyltrimethylammonium chloride cationic monomer, α-ketoglutarate, N,N'-methylenebisacrylamide, ε-polylysine and ε-polylysine-dopamine isothiocyanate functional component monomer, and polylysine. The front-end flexible detection module specifically uses a light emitter to generate light with wavelengths of 735nm and 850nm, uses a light sensor to detect the intensity of light reflected back from the human body, and calculates the local tissue oxygen saturation based on a steady-state spectral spatial resolution algorithm.

2. The local tissue oxygen saturation detection system for postoperative free flaps according to claim 1, characterized in that, The back-end signal processing module includes a core processor module, a program reset module, a USB-to-serial port module, a communication port, and a driver module. The core processor module is connected to the signal input terminal of the program reset module. The core processor module is also connected to the USB-to-serial port module to enable serial communication and program download. The core processor module is also connected to the signal input terminal of the communication port. The communication port is connected to the front-end flexible detection module. The core processor module is also connected to the signal input terminal of the transmitting module.

3. The local tissue oxygen saturation detection system for postoperative free flaps according to claim 2, characterized in that, The back-end signal processing module also includes a power supply module, which includes a battery-powered module and a power conversion module. The input of the power conversion module is connected to the output of the battery-powered module and the USB-powered module. The battery-powered module is used to provide voltage, and the power conversion module is used to increase the fixed voltage provided by the battery-powered module. At the same time, when using USB power, it is used to decrease the voltage provided by USB.

4. The local tissue oxygen saturation detection system for postoperative free flaps according to claim 1, characterized in that, The back-end signal processing module also includes a driver module and an FPC connector. The core processing module is connected to the driver module and the FPC connector, respectively, and the driver module and the FPC connector are connected to the front-end flexible detection module, respectively.

5. The local tissue oxygen saturation detection system for postoperative free flaps according to any one of claims 1-3, characterized in that, The preparation method of the front-end flexible detection module includes the following steps: First, polydimethylsiloxane (PDMS) is spin-coated and cured onto a rigid substrate to obtain a flexible material substrate layer composed of PDMS; then, conductive silver paste conforming to a pre-designed circuit pattern is prepared on the flexible substrate layer using a scraping method to form a conductive layer; then, multiple chips are connected to the pre-set target positions of the conductive silver paste layer to obtain a chip layer, which is then cured. After curing, the conductive silver paste layer forms a conductive layer. The pins of each chip are adhered to the conductive silver paste layer by applying conductive silver paste and then lightly pressing it; next, PDMS is poured onto the chip layer as a flexible encapsulation layer. After curing in an oven, the chips are fixed and protected; then, the encapsulation layer (PDMS) is treated with benzophenone solution, and a pre-crosslinked hydrogel solution is injected into a mold on the encapsulation layer, covered with a quartz glass plate, and irradiated with ultraviolet light to obtain a fully crosslinked self-adhesive antibacterial and anti-swelling hydrogel interface layer, finally obtaining the front-end flexible blood oxygen detection module.

6. The local tissue oxygen saturation detection system for postoperative free flaps according to claim 5, characterized in that, The preparation method of the hydrogel solution includes the following steps: First, 10-20 wt% acrylic acid monomer and 10-15 wt% methacryloyloxyethyltrimethylammonium chloride cationic monomer are dissolved in 10 ml of deionized water. After thorough stirring, 0.1 wt% α-ketoglutarate and 0.02 wt% N,N'-methylenebisacrylamide (MBAA) are added sequentially, and the mixture is stirred. Then, 5%-10 wt% ε-polylysine-dopamine isothiocyanate functional component (EPL-DA-ITC) monomer and 2-5 wt% ε-polylysine (EPL) are added to the above solution. After ultrasonic vibration, the mixture is degassed to obtain a pre-crosslinked hydrogel solution.

7. The local tissue oxygen saturation detection system for postoperative free flaps according to claim 2, characterized in that, The front-end flexible detection module is connected to the back-end signal processing module through an FPC flexible flat cable. One end of the FPC flexible flat cable is bonded to the conductive layer of the front-end flexible blood oxygen detection circuit through conductive silver paste, thereby realizing the connection between the FPC cable and the front-end flexible port. The other end is connected to the back-end signal processing module through a PFC connector.

Images